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Diagnosis Hematology & Blood & Marrow Transplant (BMT)


Accurate diagnosis is essential for the optimal management of hemophilia. Testing for hemophilia should be performed at a highly experienced specialized coagulation laboratory. Laboratories that do not frequently perform these specialized tests may not be able to accurately establish a diagnosis.

Most people with hemophilia are diagnosed at an early age. However, those with mild hemophilia may not be diagnosed until adulthood when they experience a bleeding episode due to trauma or surgery.

Hemophilia is diagnosed with blood tests to determine if clotting factors are missing or at low levels, and which ones are causing the problem. If you have a family history of hemophilia, it is important that your doctors know the clotting factor your relatives are missing. You will probably be missing the same one.

If you know you are a carrier of hemophilia, the testing for hemophilia in your newborn usually occurs soon after birth. These tests can be run on blood obtained from the umbilical cord or drawn from the newborn's vein. You may be advised to delay some procedures, such as circumcision, until after you learn whether your child has hemophilia.

Some families with a history of hemophilia may want to request prenatal testing, or testing before birth. This testing can be done early in pregnancy, allowing your family to make informed decisions and preparations. UCSF has genetic counselors who are available to help you with prenatal testing, if desired.

If you are pregnant and think you could be a carrier, or if you have a child diagnosed with hemophilia and are expecting another child, it is important to tell your obstetrician.

There are three ways to determine if you are a carrier:

  • Family tree If you have a son with hemophilia and have another son, brother, father, uncle, cousin or grandfather with the disorder, then you are a carrier. No additional tests are needed.
  • Clotting factor If the clotting factor level in your blood is below 50 percent of normal, you are probably a carrier and have mild hemophilia. If the clotting factor level is above 50 percent, you still may be a carrier, since other conditions can elevate the factor level. Other tests may be necessary.
  • DNA testA DNA test can look for the mutation that caused hemophilia in your son or another relative, and compare it to your DNA.

UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.